EXCLUSIVE: Princess Diana's Brother Claims Palace Plot Led to Her Death

Princess Diana's heartbroken brother believes he has solved his sister's "murder," revealing how a twisted, dirty trick possibly orchestrated by Buckingham Palace drove her to the breaking point and her eventual death in a car crash nearly 30 years ago.

Acting at the direction of the late Queen Elizabeth's unforgiving husband, Prince Philip, British intelligence officers "mounted a clever operation to drive then-Prince Charles' emotionally fragile ex-wife to the breaking point," an insider told RadarOnline.com.

Diana's brother, Charles Spencer, 62, is now telling all and exposing the plot against the People's Princess – and the treacherous whisper campaign that fueled her paranoia and desperation, leading her to ditch her longtime security team and hire the booze-guzzling driver who ended up behind the wheel in the Aug. 31, 1997, Paris wreck.

A rep for Spencer had no comment, while Buckingham Palace responded to the allegations in Spencer's book by saying in a rare statement: "While we do not comment on books as a matter of principle, His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgment and color memory in ways others do not recognize, even many years after such a loss."

Spencer claimed BBC journalist and suspected patsy Martin Bashir used fake bank statements to secure the infamous 1995 interview for the popular news show Panorama and suggest Diana was under surveillance by operatives working at the behest of the royals and MI5 agents.

"The consequences of Diana being told, 'You cannot trust anyone,' meant that she was alone that night, really, and I think that she was so convinced that she got rid of her driver, a totally innocent man," charged Spencer, referring to his sister's decision to ditch her reliable security team. He called her death "very, very preventable."

"People said, 'Oh, she was paranoid' – she wasn't paranoid," Spencer insisted. "She was convinced that she couldn't trust people because the evidence was there, and I think that left her vulnerable that night."

What's more, Bashir, who many believe was himself an unwitting player in the alleged scheme, also managed to convince Diana that her private emails were being intercepted, her phone was bugged and her car was being tracked.

"Diana was no match for the plot designed to entrap her," a high-level royal source told RadarOnline.com. "She was like a lamb to the slaughter."

The source also claimed there were "recordings of Prince Charles and his private secretary Richard Aylard planning the 'end game'" – which Spencer took to mean the divorce.

The source continued: "To Diana, however, it was evidence of a plot to kill her. The aim was to push the paranoid princess into talking publicly – a royal no-no – to give cheating Charles ammunition to force the divorce she was refusing."

Charles' affair with longtime mistress and current Queen Camilla drove Diana into the arms of several lovers, including British Pakistani cardiothoracic surgeon Dr. Hasnat Khan and producer Dodi Fayed, a Muslim – relationships the source claims led MI6 to label her a national security risk as the mother of Prince William, heir to the throne.

Diana, 36, died alongside Fayed, 42, and driver Henri Paul – and a 6,000-page French investigative file, believed by conspiracy theorists to show Diana was murdered and name her killers, has been ordered sealed for decades.